1. Field Of The Invention
The present invention relates generally to hand-held, powered machinery for cutting vegetation, and more specifically to apparatus for converting string trimmers to perform other yard care functions.
2. Description Of The Related Art
It has long been recognized that great economy and efficiency are possible when a device can be put to multiple uses. This concept has been applied liberally to powered yard care machines of the type such as small tractors, and the like, which have a power take-off able to be coupled with various apparatus for performing different tasks. In other cases, machines initially intended to be used for a single purpose are retrofitted with apparatus for performing auxiliary functions. In relation to the vegetation cutting arts, specifically, lawn mowers have a long history of use as the power-providing units for various add-on apparatus. For example, as most lawn mowing jobs leave undesirable clippings and debris on adjacent surfaces around lawn edges, numerous different blowing and vacuuming convertors for lawn mowers have been developed. Specific examples include: U.S. Pat. No. 2,983,057 issued to Erickson in 1961 for a blower attachment for a lawn mower; and, U.S. Pat. No. 3,995,348 issued to Chernosky in 1976 for a vacuum cleaner attachment for a lawn mower. And, see U.S. Pat. No. 3,142,913 issued to Jacob in 1964 for a snow blower attachment for a lawn mower. However, the maneuverability, and therefore the usefulness, of a conventional lawn mower is limited by its size, despite the versatility it might offer with access to a full range of auxiliary attachments.
The need for more nimble blowing and vacuuming apparatus for yard care spawned single-purpose, powered, units in hand-held and backpack styles. But, various drawbacks such as excessive noise, weight and cost, and especially lack of multi-function adaptability, keep these from being suited to all purposes.
Likewise, the need for more nimble grass and weed cutting and trimming apparatus fueled the popularity of powered string trimmers, and the like. And, the availability of a convenient power take-off on such hand-held devices, expectedly, spurred development of string trimmer add-on apparatus for serving other yard care purposes. Blowing and vacuuming apparatus are as useful after a trimming job as they are after lawn mowing, so various air-conducting devices exploiting the ready availability of a trimmer's easily accessible power take-off appeared. And, these have some advantages over dedicated blowing and vacuuming apparatus. For example, see U.S. Pat. Nos. 4,827,702 and 4,835,950 issued to Cerreta in 1989 which show circular collars which fit over string trimmer heads and have multiple fan blades projecting therefrom. However, Cerreta's blades, although resilient, would likely subject the user and bystanders to injury upon contact therewith, simply because of the high speeds achievable by string trimmer drive units. Further, for fans such as those in Cerreta to move significant volumes of air, their blade would likely need to project both axially and radially beyond the standard blade shield or guard of a conventional trimmer. Again, this subjects the user and bystanders to risks of injury.
Peterson, in U.S. Pat. No. 4,242,794 issued in 1981, and Hansen, in U.S. Pat. No. 4,187,577 issued in 1980, show add-on, centrifugal-style fan housings for electric string trimmers. Each employs an axial intake, and a tangentially-oriented output nozzle which discharges air in the same plane as the fan, parallel to the ground. However, considering the conventional electric trimmer's handle shape and end grip, the extra weight the Peterson and Hansen blowers would add to an electric trimmer's motor housing would likely make such combined apparatus very awkward to wield. And, using either to direct air in any direction other than parallel to the ground would present difficulty. Further, neither Peterson nor Hansen disclose a vacuum mode.
Comer, in U.S. Pat. No. 4,227,280 issued in 1980 shows an electric trimmer convertor capable of both vacuuming and blowing functions. Comer, as above, employs a centrifugal fan, axial intake and tangentially-oriented output. And, to switch between its blower and vacuum modes, Comer's apparatus must be removed, rotated and replaced in a different orientation. Comer's apparatus vividly highlights the functional limits of its genera by its inclusion of wheels and other accoutrements reminiscent of converted conventional lawn mowers.
The blower devices of Peterson and Hansen, and especially the blower/vacuum of Comer, are exceedingly complex for the functions they perform, and are likely to be unreasonably expensive to manufacture at a sufficient level of quality to meet consumers' expectations.
Thus, it appears that a need exists for much safer apparatus than that shown in the Cerreta patents for converting a string trimmer to a blower. And, vacuuming capability would also be desirable, but not at the expense of greatly increased weight and loss of maneuverability. Yet further, such apparatus should be easy to install and remove, and inexpensive to manufacture.